for the
Assessment and Remediation of Contaminated Sediments (ARCS) Program
Great Lakes National Program Office
U.S. Environmental Protection Agency
Chicago, Illinois

The information in this document has been funded wholly or in
part by the U.S. Environmental Protection Agency (EPA) under
Contract No. 68-C8-0062, Work Assignment No. 3-52, to Science
Applications International Corporation (SAIC). It has been subjected
to the Agency's peer and administrative review and it has been
approved for publication as an EPA document.

This report was prepared by the Engineering/Technology Work Group (ETWG) as part of the Assessment and Remediation of Contaminated Sediments (ARCS) program. Dr. Stephen Yaksich, U.S. Army Corps of Engineers (USACE) Buffalo District, was chairman of the Engineering/Technology Work Group.

The ARCS Program was managed by the U.S. Environmental Protection Agency (USEPA), Great Lakes National Program Office (GLNPO). Mr. David Cowgill and Dr. Marc Tuchman of GLNPO were the ARCS program managers. Mr. Dennis Timberlake of the USEPA Risk Reduction Engineering Laboratory was the technical project manager for this project. Mr. Stephen Garbaciak of USACE Chicago District and GLNPO was the project coordinator.

This report was drafted through Contract No. 68-C8-0062, Work Assignment No. 3-52, to Science Applications International Corporation (SAIC). Clyde Dial of SAIC was the principal author of the report, with final editing and revisions made by Mr. Garbaciak prior to publication.

The Great Lakes National Program Office (GLNPO) leads efforts to carry out the provisions of Section 118 of the Clean Water Act (CWA) and to fulfill U.S. obligations under the Great Lakes Water Quality Agreement (GLWQA) with Canada. Under Section 118(c)(3) of the CWA, GLNPO is responsible for undertaking a 5-year study and demonstration program for the remediation of contaminated sediments. GLNPO has initiated an Assessment and Remediation of Contaminated Sediments (ARCS) Program to carry out this responsibility. In order to develop a knowledge base from which informed decisions may be made, demonstrations of sediment treatment technologies are being conducted as part of the ARCS Program. Bench-scale studies on the B.E.S.T.&reg.; Solvent Extraction Process, which is the subject of this report, took place at Resources Conservation Company (RCC) in Bellevue, WA on August 5 to 9, 1991. The specific objectives for this effort were to determine process extraction efficiencies for polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs); to conduct a mass balance for solids, water, oil, PCBs and PAHs; and to examine process effects on metals, oil and grease, and several other parameters.

The B.E.S.T.&reg.; Solvent Extraction Process was tested using sediment samples obtained from the Buffalo River, Saginaw River, and Grand Calumet River. The concentration of the contaminants of concern in the sediment were 0.3 to 22 mg/kg PCBs and 3 to 220 mg/kg PAHs. The PCB and PAH concentrations of 0.2 to 0.4 and 0.4 to 37 mg/kg, respectively, were found in the treated solids. This corresponds to PCB and PAH removals of >95 to 99 percent and 65 to 96 percent, respectively. Metals analyses were performed on the treated solids and untreated sediments. The data demonstrate that the treatment process, as expected, had little affect on metal removal from the sediments. The feed sediments and treated solids were analyzed for percent moisture, oil and grease, total organic carbon (TOC), total volatile solids, and pH. Reductions in oil and grease concentrations (ranging from 80 to 99 percent) correspond to sediment PCB and PAH removal. A mass balance was also carried out as part of this study for the different constituents: solids, oil, water, PCBs, and PAHs.

The B.E.S.T.&reg.; Solvent Extraction Process was tested using sediments obtained from the Buffalo River, Saginaw River, and Grand Calumet River. The contaminants of concern in the sediments for these tests were PCBs and PAHs. Samples of the feed material and the treated solids produced using the B.E.S.T.&reg.; Solvent Extraction Process were analyzed by Battelle Marine Sciences Laboratory and RCC for residual PCB contamination. The data from these analyses are presented in Table 1.

Table 1. Battelle and RCC Data - PCB Summary

Feed
Sample

Treated
Solids
(mg/kg, dry basis)

Removal
Efficiency
(mg/kg, dry basis)

%

Battelle

RCC

Battelle

RCC

Battelle

RCC

Buffalo River

0.32

0.60

<0.3

<0.03

>6

>95

Saginaw River

21.9

21

0.24

0.18

99

99

Grand Calumet River

15.0

22

0.44

0.23

97

99

As these data obtained by RCC and Battelle demonstrate, PCB removal efficiencies for the Grand Calumet River and Saginaw River sediments complement each other. However, the removal efficiencies determined by RCC and Battelle for the Buffalo River sediment are substantially different. This can be attributed to the fact that the contaminant concentration in the raw Buffalo River sediment was close to the analytical detection limit achievable by Battelle. The potential errors associated with these data undermine the relevance of the removal efficiency obtained by Battelle for the Buffalo River sediment.

During the RCC analyses of the Buffalo River and Saginaw River sediments, residual PAH concentrations of <0.2 mg/kg per compound were found in the treated solids. Treated solids with PAH concentrations ranging from <1 to <3 mg/kg per compound were obtained for the Grand Calumet River sediment. Because RCC was unable to report lower detection limits, comparisons between RCC and Battelle data are not conclusive.

Metal analyses were performed on the treated solids and untreated sediments (see Table 11). The Battelle data demonstrate that the treatment process, as expected, had little affect on metal removal from the sediments. The RCC data cannot be compared to the Battelle data because these data were obtained using different analytical methods than those employed by Battelle. Because of the ashing of the sediment feed sample (potentially causing metals to be lost by volatilization) and because different methods were used to analyze the feed sediments and product solids, a reliable comparison of the RCC and Battelle data is not possible.

The feed sediments and treated solids were analyzed for percent moisture, oil and grease, Total Organic Carbon (TOC), volatile solids, and pH (see Table 12). As the data in Table 12 shows, the reductions in oil and grease concentrations (ranging from 80 to 99 percent) correspond to sediment PCB and PAH removal.

A mass balance was also carried out as part of this study. Table 3 summarizes the results obtained for the different constituents: solids, oil, water, PCBs, and PAHs.

Table 3. Mass Balance Summary (percent recovered)

SolidsSample

Oil

Water

PCBs

PAHs

Battelle

RCC

Battelle

RCC

Battelle

RCC

Battelle

RCC

Battelle

Buffalo River

98

97

163

112

68

70

129

70

90

Saginaw River

99

98

192

137

74

82

80

280

240

Grand Calumet River

92

86

69

97

78

75

94

64

11

Assuming that a full-scale application of this technology occurred and a volume of 500,000 tons of sediment required treatment, RCC estimated that it would cost approximately $150 to $250/ton to treat the material. The cost is dependent on the quantity of material processed, the cleanup target and the settling characteristics of the waste. The waste would be treated at a rate of 200 to 300 tons per day using the B.E.S.T.&reg.; Model 615 Unit operated on a 24-hour-per-day basis. This estimate includes mobilization/demobilization costs but does not account for costs associated with site excavation, civil work, applicable taxes, pre-screening needs, and overall site management and disposition of the product oil.

Small vials of the residuals from the treatability test were retained and given to the EPA Technical Project Manager for the GLNPO for "show" purposes. All quantities of the test products (water, solids, and oil residuals) from each treatability test were sent to the analytical laboratory, Battelle Marine Sciences Laboratory, for analysis. Due to the quantities generated from the tests, none were retained and shipped to EPA for possible further treatability studies.